This invention relates in general to means affixed to the rims of wheels of ground surface vehicles for support of the sidewalls of pneumatic tires on said wheels and in particular to those means which provide lateral support against sheer deformation of the tires.
It has long been known that pneumatic tires mounted on the wheels of a ground surface vehicle deform laterally when the vehicle is turning. During a turn the inertia of the vehicle urges the vehicle to continue in a straight line, but the friction between the turned front wheels and the surface upon which the vehicle is travelling creates a path of least resistance in the direction of the turn. The friction acts as a sheering force on the tread of the tires in contact with the ground surface, especially the front tires, causing the tires to deform laterally (sheer deformation) toward the center of the turn. The magnitude of the sheering force or friction on any given tire is, at least in part, a function of the weight being carried by that tire. The tires on the outside of the turn are therefore subjected to greater sheer forces than the inside tires because the centrifugal force acting on the vehicle during the turn tends to shift the weight of the vehicle to the outside tires.
During low and moderate speed turns, such as turns made in the normal course of everyday driving, the deformation of the tires is not a problem because the sidewalls of typical tires are stiff enough to keep the degree of deformation within safe limits. However, during high speed turns, such as those made during a vehicle race, the deformation becomes a serious problem. If the degree of deformation becomes too large it can fold the tire toward the center of the turn and significantly reduce the tread area in contact with the surface. Such a reduction can cause the tires to break into a slide and thereby reduce operator control of the vehicle. Furthermore, the deformation significantly reduces the useful life of the tires by causing increased wear and tear on them.
This invention presents a retrofittable device which adds lateral support to such tires, especially to the inboard sides of the tires, in order to make them effectively laterally stiffer and more resistant to the above-described sheer deformation.
U.S. Pat. No. 412,699 shows the use of sidewall wheel flanges to laterally confine and crimp a solid rubber tire to a wheel. U.S Pat. No. 772,818 presents another tire with a high walled rim to confine and in one case to crimp the tire onto the wheel rim. U.S. Pat. No. 1,113,356 presents side plates to provide support under vertical load. All of these patents are for wheels and rims which did not involve pneumatic tires and they are either for the purpose of confining the tires to the rims and/or for vertical support. They are also adapted to tires which are very different from the type of tires commonly in use today.
U.S. Pat. No. 1,885,901 presents a tubed tire in a wheel which has annular wall plates or disk members bolted to the brake drums of the wheel by strengthening disks. These plates or disk members actually form the bead area.
U.S. Pat. No. 2,426,628 shows another wheel with relatively high rim walls which provide vertical support for a mechanism which comes into play when the tire becomes deflates as in a punctured tire. In this patent and the others described above the rim flanges are designed to accommodate the type of tires which were in use when those inventions were patented. They were apparently needed to provide vertical support for the sidewalls to offset the deforming of the side walls due to vertical loads. None of the patents disclose lateral support necessary to prevent sheer induced deformation of the tires under high speed turns.
U.S. Pat. No. 4,427,046 presents a pneumatic tire with an integral stiffening member in the bead and lower sidewall area.
U.S. Pat. No. 4,253,511 presents a specialized rim which has horizontal bracing flanges which are actually stop means for vertical columns which are an integral part of the sidewalls of the tires. When the tires are deflated or underinflated, the load on the tire deforms it up to a point where the sidewall columns abut the rim flanges. This has the effect of minimizing the deformation.
U.S. Pat. No. 4,287,924 presents a tire with self-supporting sidewalls for uninflated situations.
U.S. Pat. No. 4,168,732 presents rims with bolted-on annular rings. The rings are to prevent excessive deformation of the tire by overload conditions. This patent and the last two require specialized, unconventional tires adapted to a specialized rim. Also, they are not intended to prevent sheer induced deformation of the tire under dynamic conditions.
Other advantages and attributes of this invention will be discussed or will be readily apparent upon a reading of the text hereinafter.